v3dfx with multiple channels not working

I have an application that is trying to display 1 to 4 channels of NTSC (720x480 YUV) video using the v3dfx component. It works well for a single channel. However, when I attempt to display 2, 3 or 4 channels, I do not see any video. All I see is yellow and the performance is poor.

I've attached a file that shows the code that I am using to display 2 channels.


I could really use some TI help on the one. I have been trying to get this working for several weeks now with little success.